This invention relates to rotary internal combustion engines, and more particularly, to improved multi-piece apex seal assemblies therefore.
Rotary engine apex seals have historically worn too fast, thus limiting the life of the engine. Various attempts have been made to reduce apex seal wear by using lower friction and/or more wear resistant materials and by reducing the factors and forces which contribute to wear. For example, tilted apex seals are shown in U.S. Pat. No. 3,124,439, issued July 28, l964 to Froede, in U.S. Pat. No. 3,269,369, issued August 30, 1966 to Ehrhardt, in U.S. Pat. No. 3,853,438, issued December 10, 1974 to Sato, and in U.S. Pat. No. 4,056,338, issued November 1, 1977 to Eiermann. Multi-piece apex seals have also been proposed. For example, see U.S. Pat. No. 4,317,648, issued March 2, 1982 to Shimizu et al. and U.S. Pat. No. 4,358,259, issued November 9, 1982 to Morita. However, it would be desirable to provide an apex seal assembly with improved wear capabilities for use in the high speed and high temperature environment of a stratified charge rotary internal combustion engine.